filter design: how to compensate temp drift

[y99lx]

Dear cavity filter experts,
Please discuss the soltions to improve the stability over temperature varying. Are there some commonly used solutions?

thanks
y99lx

 

[biff44]

plated invar cavities, tuning screws with a controlled mechanical expansion vs. temperature.

 

[y99lx]

thanks, but the expansion is usually not controllable. Is there any special design consideration for this problem?

 

[biff44]

You make the cavity and tuning screw out of materials with different coefficients of expansion. As one drifts one way over temperature, the other brings it back.

 

[kspalla]

Increase the thickness and fix to heat sink